Authorization for new, replacement fighter jets to Poland could take a long time, though discussions between Warsaw and Washington are still underway.

A White House spokesman told POLITICO that they are working with the Poles and other NATO allies on the issue.

Several Eastern European countries like Poland, Bulgaria and Slovakia have Russian-made aircraft in their inventories but are hesitant to give them up without assurances from the U.S. that they could replace them.

Poland has been modernizing its aircraft fleet since 2006 when it first started flying F-16s, and in 2020 signed a $4.6 billion deal for 32 F-35s, the first of which will arrive in 2024, making those older Russian-made planes expendable.

The issue of sending aircraft into the fight is more complicated than the effort by many European countries to send weapons to Ukraine. In the last few days, a steady stream of planes from the US and Britain have landed in Poland filled with missiles.

Over the past several weeks, the U.S. has sent 12,000 troops to Europe to back up nervous allies along NATO's Eastern front, the majority of which went to Poland to join the 4,000 U.S. troops already stationed there. If the flood of war refugees overwhelms Polish and E.U. authorities, the troops could be called on to assist.

The White House is not opposed to Poland transferring planes to Ukraine, according to the spokesman. Russian officials will attack any convoys carrying weapons.

The issue of transferring American F-16s to Poland is complicated by the fact that the planes may not always be legal to transfer overseas.

Zelenskyy spoke with senators on Saturday and urged them to impose oil sanctions on Russia and send planes, drones and missiles to Ukraine.

The European Union security chief made a startling announcement last weekend that several countries would soon ship fighter jets to the border for transfer to the Ukrainian armed forces.

The Ukrainian officials told POLITICO that several of their pilots had already arrived in Poland for the handoff, but the deal fell through. The idea was rejected by Bulgaria and Slovakia.

The $350 million in military assistance Biden approved recently has already been shipped, with the rest expected in the coming days.